Parameter-free calculations of X-ray spectra with FEFF9
Parameter-free calculations of X-ray spectra with FEFF9
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DOI：
10.1039/b926434e
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发表时间：
2010-01-01
影响因子：
3.3
通讯作者：
Jorissen, Kevin
中科院分区：
文献类型：
--
作者：
Rehr, John J.;Kas, Joshua J.;Jorissen, Kevin
我们简要地回顾了我们的实空间绿色函数（RSGF）的方法计算的X射线光谱，专注于最近开发的参数自由模型占主导地位的多体效应。虽然RSGF方法已被广泛用于近边（XANES）和扩展（EXAFS）范围，以前的实现依赖于半现象学方法，如。例如，在一个实施例中，等离子体极点模型的自能，屏蔽芯孔效应的最终状态规则，和相关的德拜模型的振动阻尼。在这里，我们描述了如何这些近似可以被替换为有效的从头算模型，包括一个多极模型的自能，非弹性损失和多电子激发;一个线性响应的核心孔的方法;和一个Lanczos的方法德拜-沃勒效应。我们还讨论了这些模型的实现和软件改进的FRES 9代码，以及一些例子。
We briefly review our implementation of the real-space Green's function (RSGF) approach for calculations of X-ray spectra, focusing on recently developed parameter free models for dominant many-body effects. Although the RSGF approach has been widely used both for near edge (XANES) and extended (EXAFS) ranges, previous implementations relied on semi-phenomenological methods, e. g., the plasmon-pole model for the self-energy, the final-state rule for screened core hole effects, and the correlated Debye model for vibrational damping. Here we describe how these approximations can be replaced by efficient ab initio models including a many-pole model of the self-energy, inelastic losses and multiple-electron excitations; a linear response approach for the core hole; and a Lanczos approach for Debye-Waller effects. We also discuss the implementation of these models and software improvements within the FEFF9 code, together with a number of examples.